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Source code

void AsaNavigationView::mouseMoveEvent(QMouseEvent *event){
  QGraphicsView::mouseMoveEvent(event);
  PositionFrame->setX(event->x()-FrameWidth/2);
  PositionFrame->setY(event->y()-FrameHeight/2);
  checkPositionValidity();
  
  QPointF middle( (PositionFrame->x()+FrameWidth/2)*SizeFactor*ScaleFactor,  (PositionFrame->y()+FrameHeight/2)*SizeFactor*ScaleFactor);
  emit movePositionFrame(middle); //send the centerPosition of the red rectangle to the big View
  
  
}



void AsaNavigationView::setSize(qreal w,qreal h){ //this is called in the beginnin or if the size of the big scene has changed

  const int FixedMaxWidth = 150;
  const int FixedMaxHeight = 100;
  
  SizeFactor = w/FixedMaxWidth;
  
  if( int(h/SizeFactor) < FixedMaxWidth ){
	this->setFixedSize( 150, h/SizeFactor );
  }
  else{
	SizeFactor = h/FixedMaxHeight;
	this->setFixedSize( w/SizeFactor, 100);
  }
  
  
  
}


void AsaNavigationView::setFrameSize(qreal w, qreal h){
  
  InitialFrameWidth = int(w/SizeFactor); //since there are a lot of multiplications width float and integer there would be a great loss due to rounding so I keep a initial size
  InitialFrameHeight= int(h/SizeFactor);
  
  FrameWidth = InitialFrameWidth/ScaleFactor;
  FrameHeight= InitialFrameHeight/ScaleFactor;
  
  drawFrame();
  
}


void AsaNavigationView::setScaleFactor(float s){
  
  ScaleFactor=s;
  
  FrameWidth = InitialFrameWidth/ScaleFactor;
  FrameHeight= InitialFrameHeight/ScaleFactor;
  
  drawFrame();
  
}



void AsaNavigationView::setFramePosition(const QPointF &pos){
  QPointF MiddlePosition;
  MiddlePosition.setX(pos.x()/SizeFactor/ScaleFactor);
  MiddlePosition.setY(pos.y()/SizeFactor/ScaleFactor);
  
  QPointF TopRightCorner;
  TopRightCorner.setX(MiddlePosition.x()-FrameWidth/2);
  TopRightCorner.setY(MiddlePosition.y()-FrameHeight/2);
  PositionFrame->setPos(TopRightCorner);
  
}




void AsaNavigationView::checkPositionValidity(){  	////////////here is probably the cause of the errors
  
  QPointF TopLeftFrameCorner = this->mapFromScene( PositionFrame->x(), PositionFrame->y() );
  QPointF BottomRightFrameCorner = this->mapFromScene( PositionFrame->x()+FrameWidth, PositionFrame->y()+FrameHeight );
  
  QPointF TopLeftSceneCorner = this->mapToScene(0,0);
  QPointF BottomRightSceneCorner = this->mapToScene( this->width(), this->height() );
  
  
  if(  TopLeftFrameCorner.x() <= TopLeftSceneCorner.x() )
	PositionFrame->setX( TopLeftSceneCorner.x() );
  
  if(TopLeftFrameCorner.y() <= TopLeftSceneCorner.y())
	PositionFrame->setY(TopLeftSceneCorner.y() );
  
  if( BottomRightFrameCorner.x() >= BottomRightSceneCorner.x() ){
	PositionFrame->setX( BottomRightSceneCorner.x()-FrameWidth);
  }
  
  if( BottomRightFrameCorner.y() >= BottomRightSceneCorner.y() )
	PositionFrame->setY( BottomRightSceneCorner.y()-FrameHeight );
}



void AsaNavigationView::drawFrame(){

  QPixmap TempRect(FrameWidth, FrameHeight);
  
  QPainter painter(&TempRect);
  painter.setPen( QPen(Qt::red, 1) );
  painter.fillRect(0,0,FrameWidth,FrameHeight, Qt::green);
  painter.drawRect(0,0,FrameWidth-1,FrameHeight-1);
  PositionFrame->setPixmap(TempRect); 
  checkPositionValidity(); 
}